1. Field of the Invention
The present invention relates to the establishment of a fluid impervious seal about a space which is subject to pressure fluctuations and, particularly, to the creation of a seal between the block and cylinder head of an internal combustion engine. More specifically, this invention is directed to metallic head gaskets and, especially, to such gaskets wherein sealing about the ends of the cylinders is accomplished by means of integral resilient beads and wherein a pair of coaxial deformation limiters are provided within the gasket for each bead to prevent permanent deformation thereof. Accordingly, the general objects of the present invention are to provide novel and improved methods and articles of such character.
2. Description of the Prior Art
Metallic cylinder head gaskets are, of course, well-known in the art. Published German Patent Application 195 13 361 discloses such a gasket wherein resilient sealing beads, arranged coaxially with respect to the combustion chamber openings, are each provided with a pair of deformation limiters. The deformation limiters of each pair cooperate to prevent excessive deformation of the associated sealing bead in areas displaced both radially inwardly and radially outwardly from the bead. The provision of such inner and outer deformation limiters results in the compression of the beads in the clamped condition of the gasket being directed virtually perpendicularly with respect to the sealing plane. It has been found to be particularly advantageous to utilize such cooperating inner and outer deformation limiters when the gasket is employed on an engine having a block formed of a relatively light-weight material and cylinder liners. In such an operating environment, there is a risk of the effectiveness of the inner deformation limiter being reduced as a result of the cylinder liner subsiding, i.e., as a consequence of the operating conditions and factors such as different coefficients of thermal expansion of the head, block and liner. Under such circumstances, an unacceptable degree of deformation of the bead will be reliably prevented by the outer deformation limiter.
In the prior art, as exemplified by the above-referenced publication, the outer deformation limiters are customarily in the form of rings mounted on a carrier plate. The centering and attaching of such rings, as well as the shaping of the relatively thick carrier plates, are laborious tasks which have significantly increased gasket cost. There has, accordingly, been a long-standing desire in the art for a metallic cylinder head gasket, having inner and outer bead deformation limiters, which can be more efficiently manufactured when compared to the prior art.